Setting :page-toclevels: greater than 3 has odd results.
Three is documented as the maximum, but.... if you set say 4, then 4 levels show up, but the 4th is not indented at all.
Why is the max 3 rather than 6?
Not necessarily a bug, but setting 0 seems to make the on-this-page disappear, just like -1. I'd expect the title to appear.